LOUISVILLE, Ky., June 20 /PRNewswire/ -- For more than 50 years the drug Warfarin, (brand named Coumadin) has saved the lives of patients at risk for dangerous blood clots. According to NDC Health Pharmaceutical, more than 30 million Warfarin prescriptions were filled in 2004.

However, Warfarin routinely ranks among the top five medications most frequently associated with severe adverse drug reactions (ADR's) requiring hospitalization.

"There is no question that Warfarin has been highly successful in reducing mortality in patients with atrial fibrillation, or those at risk of ischemic stroke," explained PGXL Laboratories President Roland Valdes Jr., Ph.D. FACB. "However, the frequent occurrence of genetic variations that effect how patients metabolize and respond to the medication has made Warfarin a mixed blessing, until now."

The clinical pharmacology advisory committee reporting to the FDA in November 2005 reviewed the application of two diagnostic tests for the treatment of patients with Warfarin.

The committee unanimously agreed that "sufficient mechanistic and clinical evidence exists to support the recommendation: to use lower doses of Warfarin for patients with genetic variations in CYP2C9 and/or VKORC1 that lead to reduced activities."

The report continued, "Genotyping patients in the induction phase of Warfarin therapy would reduce adverse events and improve achievement" of a stable level of anticoagulation.

The FDA is expected to announce in the coming months new labeling for Warfarin, recommending genetic testing to ensure the drug's safe use. Scientists at PGXL Laboratories currently offer both of these tests trough their CLIA certified clinical testing laboratory.

According to Valdes, PGXL Laboratories has also co-developed a combination CYP2C9 and VKORC1 genetic test with Tm Bioscience to support the FDA recommendations. Tm Bioscience intends to secure regulatory clearance for this combined test.

"These tests identify patients who may have a Warfarin sensitivity, which can lead to severe adverse events including death," explained Mark Linder, PGXL vice president of operations. "They also identify patients who may be Warfarin-resistant, meaning that they remain at risk for dangerous blood clots with normal doses of the medication.

"Having this detailed information will be invaluable to physicians prescribing Coumadin."

The Warfarin tests are the latest addition to the pharmacogenetic testing and education services offered by PGXL Laboratories. PGXL offers DNA testing to help physicians, hospitals, clinics, and laboratories, better manage their patients on certain medications, including all prescription drugs that have FDA labeling recommending Pharmacogenetic testing.

PGXL Laboratories, headquartered in Louisville, Ky., was the first lab certified by the Clinical Laboratory Improvement Amendment (CLIA) to exclusively offer pharmacogenetic testing.